Their contracts are expected to include a bigger share of the profits from rerun sales and development deals with Warner Bros. TV, the studio that produced Friends and is now responsible for the top-rated The Big Bang Theory for CBS.

The raise is a substantial jump from the reported $300,000-plus an episode the trio had been earning. The new rate would easily make the three actors among the highest paid on TV.

Simon Helberg and Kunal Nayyar – who play Howard Wolowitz and Raj Koothrappali – still need to iron out their new contracts before production on the eighth season can resume, one insider tells PEOPLE.

If all goes well, the cast could return to work in Burbank, California, as early as this Wednesday in preparation for the comedy’s Sept. 22 return on CBS.

Melissa Rauch and Mayim Bialik, who play Bernadette Rostenkowski and Amy Farrah Fowler, already have deals in place.

The earning power of the TBBT actors reflects the immense popularity of the comedy, which, at 20.3 million viewers, just wrapped its most-watched season yet, CBS tells PEOPLE.

Since TBBT reruns make truckloads of cash for Warner Bros. TV, interest in the actors’ salaries has always been high – a phenomenon not lost on Kaley Cuoco.

“I would be lying if I said I couldn’t do Penny with my eyes closed,” Cuoco told EW in 2012. “It’s such second nature to me now. But if I ever do get those moments of, ‘God, this feels the same,’ I just read those articles about how much money I make and think, ‘You know, it’s not so repetitive anymore!’ ”